The present invention relates to wireless communications systems and methods, and more particularly, to wireless mobile data communications systems.
Wireless communications technologies are widely used to provide communications services. For example, cellular mobile telephone systems are used throughout the world to provide telephone voice services. Wireless communications services are also widely used to provide text and other messaging services, such as paging services.
A growing market for the application of wireless communications technologies is the provision of data communications services. For example, wireless mobile data communications systems are now used to provide wireless wide area networking such that mobile users, such as salespeople, maintenance personnel, and the like, may use networked applications. Wireless mobile data communications systems may also be used to provide mobile internet services.
A conventional Cellular Digital Packet Data (CDPD) communications system 110 is illustrated in FIG. 1. The CDPD system 110 includes multiple Mobile Data Intermediate Systems (MD-IS) 111 and a Network Management System (NMS) 112 that are linked by a CDPD backbone network 113. The MD-IS's 111 control communications with respective groups of Mobile Data Base Stations (MDBSs) 116, which are shown as coupled to the CDPD backbone network by a router 114 and frame relay network 115. The MD-IS's 111, the MDBSs 116 and associated network hardware provide means for Mobile End Stations (M-ESs) 120 to communicate data with one another and/or with an external network (e.g., an internet) 130. Commonly, the MDBSs 116 communicate with the MD-ISs 111 and the NMS 112 using a transport layer/network layer stack such as TCP/IP (Transport Control Protocol over Internet Protocol), UDP/IP (User Datagram Protocol over Internet Protocol) or TP4/CNLP (Transport Protocol 4 over Connectionless Network Protocol). A detailed discussion of CDPD may be found in “Cellular Digital Packet Data Networks,” by Budka et al., Bell Labs Technical Journal, Summer 1997, pp. 164–181. Other wireless mobile data communications systems include General Packet Radio System, which provides packet data communications for Global System for Mobile Communications (GSM) and other Time-Division Multiple Access (TDMA) systems, as well as CDMA (Code Division Multiple Access) and UMTS (Universal Mobile Telecommunications System).
Wireless mobile data communications systems commonly use existing wireless voice communications infrastructure. For example, CDPD services may be provided by fitting existing Advanced Mobile Phone System (AMPS) base stations with supplemental hardware that enables these base stations to serve as MDBSs in the CDPD network. It is generally desirable that the installation and maintenance of such MDBSs be efficient and cost effective.